Stellite 25
About Stellite 25
Name and Equivalent Name: Stellite 25, Cobalt-Chromium Alloy 25 or Haynes 25, holds the UNS designation R30605. It conforms to ASTM F90, B426, DIN/EN 2.4964, and BS 3375: HR40 standards. Stellite 25 is also standardized under AMS 5796, ISO 5832-5, ASME SB-90, and GB/T 15025: CoCrW25, meeting the requirements of NACE MR0175 for corrosion resistance.
Stellite 25 Basic Introduction
Stellite 25 is a premium cobalt-chromium alloy known for its excellent resistance to wear, corrosion, and oxidation at high temperatures. Its ability to withstand mechanical stress and thermal fatigue makes it a preferred material for aerospace, gas turbines, and chemical processing applications. The alloy’s high strength and toughness under extreme conditions ensure durability in critical components.
Designed for long-term use in harsh environments, Stellite 25 maintains its mechanical properties across a broad temperature range, from cryogenic conditions to elevated temperatures near 850°C. Its moderate creep resistance and excellent thermal fatigue performance are reliable for components exposed to frequent thermal cycling.
Alternative Superalloys of Stellite 25
Stellite 6 is often used as an alternative for applications requiring more wear resistance but less corrosion protection. Stellite 21 offers enhanced corrosion resistance but lower strength at elevated temperatures. Inconel 625 or Hastelloy C276 are viable alternatives for extreme high-temperature applications due to their superior oxidation resistance.
Other alternatives include Rene 41 and Nimonic 90, used in aerospace components for their creep resistance and fatigue strength. Haynes 188 is another cobalt-based alloy used for similar high-temperature applications, providing slightly better oxidation resistance but comparable mechanical properties.
Stellite 25 Design Intention
Stellite 25 was developed to withstand extreme mechanical stress, high temperatures, and aggressive environments. Its primary design goal is to balance corrosion resistance, thermal stability, and wear resistance, making it ideal for aerospace components, gas turbines, and chemical reactors.
The inclusion of chromium and tungsten improves both corrosion and oxidation resistance. The alloy’s low carbon content enhances toughness while minimizing brittleness. It is often used in valves, turbine blades, and high-performance bearings, where long-term reliability is essential, especially under fluctuating thermal conditions.
Stellite 25 Chemical Composition
The chemical composition of Stellite 25 includes high chromium for corrosion resistance and tungsten to enhance strength at high temperatures. Nickel provides oxidation resistance, while low carbon content ensures toughness.
Element | Composition (%) |
|---|---|
Cobalt (Co) | Balance |
Chromium (Cr) | 19.0-21.0 |
Tungsten (W) | 14.0-16.0 |
Carbon (C) | Max 0.05 |
Nickel (Ni) | 9.0-11.0 |
Iron (Fe) | Max 1.0 |
Silicon (Si) | Max 1.0 |
Manganese (Mn) | Max 1.0 |
Stellite 25 Physical Properties
The physical properties of Stellite 25 enable it to retain strength and resist oxidation under harsh operating conditions.
Property | Value |
|---|---|
Density (g/cm³) | 8.46 |
Melting Point (°C) | 1350 |
Thermal Conductivity (W/(m·K)) | 14 |
Elastic Modulus (GPa) | 209 |
Metallographic Structure of Stellite 25 Superalloy
Stellite 25 has a solid cobalt-based matrix strengthened by dispersed tungsten and chromium carbides. The uniform distribution of carbides enhances wear resistance while maintaining mechanical integrity at high temperatures. This structure provides excellent resistance to surface degradation, making the alloy suitable for demanding environments.
The alloy’s metallographic structure ensures thermal stability, with nickel enhancing oxidation resistance. Low carbon levels ensure the alloy remains ductile, preventing cracking under mechanical loads. The metallurgical composition supports high creep resistance and effective stress management, extending the lifespan of components operating under harsh conditions.
Stellite 25 Mechanical Properties
Stellite 25 provides excellent mechanical strength and fatigue resistance, making it suitable for applications in aerospace and high-temperature systems.
Property | Value |
|---|---|
Tensile Strength (MPa) | 750-850 |
Yield Strength (MPa) | 450 |
Hardness (HRC) | 40-45 |
Elongation (%) | 10-12% |
Elastic Modulus (GPa) | 200 |
Key Features of Stellite 25 Superalloy
High-Temperature Resistance Stellite 25 retains mechanical strength and stability at elevated temperatures, making it ideal for aerospace components and gas turbines. It can operate efficiently under temperatures as high as 850°C, resisting creep and thermal fatigue.
Wear and Corrosion Resistance The alloy offers superior resistance to wear, making it suitable for valve seats, bearings, and other moving components. Its high chromium content ensures protection against corrosion in aggressive chemical environments.
Oxidation Resistance With nickel and chromium, Stellite 25 withstands oxidation, allowing long-term use in high-temperature environments. This property makes it a preferred material for jet engine components and heat exchangers.
Toughness and Ductility Stellite 25’s low carbon content ensures high toughness and prevents brittleness, allowing it to withstand mechanical stress without cracking. The alloy’s ductility ensures durability even under impact loads.
Long Service Life in Harsh Environments Designed for demanding conditions, Stellite 25 offers reliable performance with minimal maintenance. Its ability to resist wear, corrosion, and thermal fatigue ensures a long service life in aerospace, chemical, and power generation applications.
Stellite 25 Superalloy’s Machinability
Stellite 25 can be used in Vacuum Investment Casting due to its ability to maintain surface integrity and resist oxidation during complex mold processes. Its high chromium content ensures a durable, corrosion-resistant finish, making it ideal for precision casting components in high-temperature environments. Vacuum Investment Casting.
Stellite 25 is unsuitable for Single Crystal Casting due to its multi-grain microstructure, which does not align with the single-crystal requirements. The alloy's mechanical properties and structural composition are designed for high-wear resistance rather than single-crystal growth applications. Single Crystal Casting.
Stellite 25 can be utilized in Equiaxed Crystal Casting because of its balanced mechanical strength and thermal resistance. The equiaxed structure ensures the alloy can handle thermal stress while maintaining wear resistance for industrial components. Equiaxed Crystal Casting.
Stellite 25 is not ideal for Directional Casting, as it lacks the specific grain alignment required for this casting technique. Its structure and properties are optimized for durability and corrosion resistance rather than directional grain growth. Superalloy Directional Casting.
Stellite 25 can perform well in Powder Metallurgy Turbine Discs, offering corrosion resistance and thermal stability. However, precise control over porosity and alloy composition is required to meet the strict demands of turbine components. Powder Metallurgy Turbine Disc.
Stellite 25 is not recommended for Precision Forging due to its high hardness, which makes it difficult to deform into intricate shapes. Its strengths lie more in wear resistance and corrosion protection. Superalloy Precision Forging.
Stellite 25 can be used in Superalloy 3D Printing, although challenges arise due to its hardness. With advanced techniques, it is possible to fabricate wear-resistant components suitable for demanding applications. Superalloy 3D Printing.
Stellite 25 is highly compatible with CNC Machining, offering excellent machinability when using specialized tools and techniques to avoid thermal stress buildup. Its wear-resistant properties make it ideal for precision components. CNC Machining.
Stellite 25 is well-suited for Superalloy Welding, offering good compatibility with advanced welding techniques. Its low carbon content minimizes the risk of cracking and ensures stable performance at high temperatures. Superalloy Welding.
Stellite 25 can undergo Hot Isostatic Pressing (HIP) to enhance its density and mechanical properties, ensuring reliable performance in harsh environments. HIP improves fatigue resistance, making the alloy ideal for aerospace and industrial applications. Hot Isostatic Pressing (HIP).
Stellite 25 Superalloy Applications
In Aerospace and Aviation, Stellite 25 is used for engine components such as bearings, bushings, and fuel nozzles, ensuring high wear resistance and durability in harsh conditions. Aerospace and Aviation.
For Power Generation, it is employed in turbines and valve seats, offering excellent resistance to corrosion and thermal fatigue over extended operation periods. Power Generation.
In the Oil and Gas industry, Stellite 25 is used in drilling components and valve trims, where its corrosion resistance ensures reliable performance under harsh chemical environments. Oil and Gas.
The alloy’s high-temperature stability in the Energy sector makes it suitable for heat exchangers and other equipment exposed to extreme conditions. Energy.
Stellite 25 is valuable in marine applications, such as pump components and valves, as it resists saltwater corrosion and maintains wear resistance. Marine.
Mining uses it for drill bits, crusher components, and wear plates, extending service life in abrasive environments. Mining.
In the Automotive industry, Stellite 25 is applied to high-performance components, such as exhaust valves, to withstand extreme temperatures and wear. Automotive.
The alloy ensures corrosion resistance in aggressive environments for Chemical Processing, making it ideal for reactor components and pumps. Chemical Processing.
In the Pharmaceutical and Food industries, Stellite 25 is used for valves and equipment in sterile environments, where wear resistance and corrosion protection are essential. Pharmaceutical and Food.
It is found in weapon systems and aerospace applications for military and defense, ensuring reliability in demanding conditions. Military and Defense.
In Nuclear applications, Stellite 25 provides corrosion resistance for reactor components, ensuring safe and long-lasting performance. Nuclear.
When to Choose Stellite 25 Superalloy
Choose Stellite 25 when high wear resistance, corrosion protection, and thermal stability are critical requirements. This alloy is ideal for custom superalloy parts exposed to extreme environments, such as aerospace turbines, chemical reactors, and marine applications. Its ability to withstand high temperatures while maintaining mechanical strength ensures reliability and long-term performance, even in the most challenging conditions.
Stellite 25’s versatility extends to various industries, including aerospace, energy, and automotive, making it an excellent choice for critical components that demand high durability. If your project requires materials that can handle intense wear, corrosion, and thermal cycling, custom superalloy parts like Stellite 25 are the optimal solution. Custom superalloy parts.
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